1. Lex Luthor
One of the best things about Superman is that he represents the best parts of humanity. Apply that to Lex but change best for worst. Lex's most endearing traits as a villain include his greed, his delusional belief that Superman is a force of evil and that he is the step forward humanity needs to idolise instead. As such, Lex's appearances are always a treat for me. Oh and Action Comics #894 where Lex discusses his atheism was full of so much brilliance.
The ying to Batman's yang, the tails to his heads etc. The Joker is the ultimate example of the kind of evil Batman has sworn to fight against. The dilemna that Batman might be responsible for his creation only adds to the Joker's appeal. There can be no Batman villain more quintessential than the Joker.
In all the DC Universe, not one has posed as consistently great a threat as Darkseid, the lord of Apokolips. His cruelty, his megolamaniac desires for universal conquest and enslavement of all living beings via the Anti-Life Equation has always captivated my interest in the character.
4. Doctor Doom
There are many reasons why Doctor Doom is so brilliant a villain. His intellect, his ruling a country with an iron fist, his arrogance and obsession with proving he is superior to Reed Richards. But the thing I like best about Doom is that he has posed a threat to everyone. Not just the Fantastic Four but Spider-Man, Thor, Black Panther, the Avengers and more. His status as the ultimate Marvel villain is why I love the guy so.
Although he might be more of an anti hero now, Johns' 'resurrection' of the character made Sinestro into a badass, controlling character rather than his previous one dimensional incarnation. It's a joy to see Sinestro's character grow.
Although Kid Loki is all well and good, he doesn't beat the menace the original posed to Thor. Countless cunning schemes enacted against his step-brother, his vile and wicked nature, even a sex change have made Loki an endearing, excellent villain in my eyes.
7. Norman Osborn
Responsible for the infamous act of killing Gwen Stacy and ending the Silver Age of comics, no villain has had as great an impact on Spider-Man's life as Norman Osborn. His insane vendetta against Peter has made his villainous acts seem even worse. As for his non Green Goblin work, well let's just say that never happened.
The cold, calculating demeanor of Brainiac has always served to make him a detached, emotionless nemesis of Superman. Add to this his later developments with a thirst for knowledge, collecting remnants or cities to add to his collection, an AI level of intelligence and incredible technology put Brainiac on my favourite villains list.
9. General Zod
Yet another quintessential foes of Superman, Zod is a character who's had many interpretations. Yet, for me, my favourites to date are his appearance in Superman II as a super powered sociopath with a complex and his last Pre Flashpoint appearance as a tyrant with somewhat sympathetic motives towards his desire to rule. What's even better is that during World of New Krypton, Zod seemed to show respect for Superman and vice versa. This kind of villainy is where comic book bad guys excel at and Zod is no exception.
10. Ra's al Ghul
Some villains want to steal money, some want to rule the world. This guy wants to wipe the slate clean from humanity's mess and start over. The leader of the League of Assassins, father to Talia and equal to Batman in nearly every way, Ra'as' plots to achieve ecological stability show him to be working for a good goal, just going about it in the wrong way. Still he's a worthy foe for Batman to face.